#if NET_2_0 || NETSTANDARD2_0
#region Apache License
//
// Licensed to the Apache Software Foundation (ASF) under one or more 
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership. 
// The ASF licenses this file to you under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with 
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#endregion

// .NET Compact Framework 1.0 has no support for System.Web.Mail
// SSCLI 1.0 has no support for System.Web.Mail
#if !NETCF && !SSCLI

using System;
using System.IO;
using System.Text;

#if NET_2_0 || MONO_2_0 || NETSTANDARD2_0
using System.Net.Mail;
#else
using System.Web.Mail;
#endif

using log4net.Core;

namespace log4net.Appender
{
  /// <summary>
  /// Send an e-mail when a specific logging event occurs, typically on errors 
  /// or fatal errors.
  /// </summary>
  /// <remarks>
  /// <para>
  /// The number of logging events delivered in this e-mail depend on
  /// the value of <see cref="BufferingAppenderSkeleton.BufferSize"/> option. The
  /// <see cref="SmtpAppender"/> keeps only the last
  /// <see cref="BufferingAppenderSkeleton.BufferSize"/> logging events in its 
  /// cyclic buffer. This keeps memory requirements at a reasonable level while 
  /// still delivering useful application context.
  /// </para>
  /// <note type="caution">
  /// Authentication and setting the server Port are only available on the MS .NET 1.1 runtime.
  /// For these features to be enabled you need to ensure that you are using a version of
  /// the log4net assembly that is built against the MS .NET 1.1 framework and that you are
  /// running the your application on the MS .NET 1.1 runtime. On all other platforms only sending
  /// unauthenticated messages to a server listening on port 25 (the default) is supported.
  /// </note>
  /// <para>
  /// Authentication is supported by setting the <see cref="Authentication"/> property to
  /// either <see cref="SmtpAuthentication.Basic"/> or <see cref="SmtpAuthentication.Ntlm"/>.
  /// If using <see cref="SmtpAuthentication.Basic"/> authentication then the <see cref="Username"/>
  /// and <see cref="Password"/> properties must also be set.
  /// </para>
  /// <para>
  /// To set the SMTP server port use the <see cref="Port"/> property. The default port is 25.
  /// </para>
  /// </remarks>
  /// <author>Nicko Cadell</author>
  /// <author>Gert Driesen</author>
  public class SmtpAppender : BufferingAppenderSkeleton
  {
    #region Public Instance Constructors

    /// <summary>
    /// Default constructor
    /// </summary>
    /// <remarks>
    /// <para>
    /// Default constructor
    /// </para>
    /// </remarks>
    public SmtpAppender()
    {
    }

    #endregion // Public Instance Constructors

    #region Public Instance Properties

    /// <summary>
    /// Gets or sets a comma- or semicolon-delimited list of recipient e-mail addresses (use semicolon on .NET 1.1 and comma for later versions).
    /// </summary>
    /// <value>
    /// <para>
    /// For .NET 1.1 (System.Web.Mail): A semicolon-delimited list of e-mail addresses.
    /// </para>
    /// <para>
    /// For .NET 2.0 (System.Net.Mail): A comma-delimited list of e-mail addresses.
    /// </para>
    /// </value>
    /// <remarks>
    /// <para>
    /// For .NET 1.1 (System.Web.Mail): A semicolon-delimited list of e-mail addresses.
    /// </para>
    /// <para>
    /// For .NET 2.0 (System.Net.Mail): A comma-delimited list of e-mail addresses.
    /// </para>
    /// </remarks>
    public string To
    {
      get { return m_to; }
      set { m_to = MaybeTrimSeparators(value); }
    }

    /// <summary>
    /// Gets or sets a comma- or semicolon-delimited list of recipient e-mail addresses 
    /// that will be carbon copied (use semicolon on .NET 1.1 and comma for later versions).
    /// </summary>
    /// <value>
    /// <para>
    /// For .NET 1.1 (System.Web.Mail): A semicolon-delimited list of e-mail addresses.
    /// </para>
    /// <para>
    /// For .NET 2.0 (System.Net.Mail): A comma-delimited list of e-mail addresses.
    /// </para>
    /// </value>
    /// <remarks>
    /// <para>
    /// For .NET 1.1 (System.Web.Mail): A semicolon-delimited list of e-mail addresses.
    /// </para>
    /// <para>
    /// For .NET 2.0 (System.Net.Mail): A comma-delimited list of e-mail addresses.
    /// </para>
    /// </remarks>
    public string Cc
    {
      get { return m_cc; }
      set { m_cc = MaybeTrimSeparators(value); }
    }

    /// <summary>
    /// Gets or sets a semicolon-delimited list of recipient e-mail addresses
    /// that will be blind carbon copied.
    /// </summary>
    /// <value>
    /// A semicolon-delimited list of e-mail addresses.
    /// </value>
    /// <remarks>
    /// <para>
    /// A semicolon-delimited list of recipient e-mail addresses.
    /// </para>
    /// </remarks>
    public string Bcc
    {
      get { return m_bcc; }
      set { m_bcc = MaybeTrimSeparators(value); }
    }

    /// <summary>
    /// Gets or sets the e-mail address of the sender.
    /// </summary>
    /// <value>
    /// The e-mail address of the sender.
    /// </value>
    /// <remarks>
    /// <para>
    /// The e-mail address of the sender.
    /// </para>
    /// </remarks>
    public string From
    {
      get { return m_from; }
      set { m_from = value; }
    }

    /// <summary>
    /// Gets or sets the subject line of the e-mail message.
    /// </summary>
    /// <value>
    /// The subject line of the e-mail message.
    /// </value>
    /// <remarks>
    /// <para>
    /// The subject line of the e-mail message.
    /// </para>
    /// </remarks>
    public string Subject
    {
      get { return m_subject; }
      set { m_subject = value; }
    }

    /// <summary>
    /// Gets or sets the name of the SMTP relay mail server to use to send 
    /// the e-mail messages.
    /// </summary>
    /// <value>
    /// The name of the e-mail relay server. If SmtpServer is not set, the 
    /// name of the local SMTP server is used.
    /// </value>
    /// <remarks>
    /// <para>
    /// The name of the e-mail relay server. If SmtpServer is not set, the 
    /// name of the local SMTP server is used.
    /// </para>
    /// </remarks>
    public string SmtpHost
    {
      get { return m_smtpHost; }
      set { m_smtpHost = value; }
    }

    /// <summary>
    /// Obsolete
    /// </summary>
    /// <remarks>
    /// Use the BufferingAppenderSkeleton Fix methods instead 
    /// </remarks>
    /// <remarks>
    /// <para>
    /// Obsolete property.
    /// </para>
    /// </remarks>
    [Obsolete("Use the BufferingAppenderSkeleton Fix methods")]
    public bool LocationInfo
    {
      get { return false; }
      set {; }
    }

    /// <summary>
    /// The mode to use to authentication with the SMTP server
    /// </summary>
    /// <remarks>
    /// <note type="caution">Authentication is only available on the MS .NET 1.1 runtime.</note>
    /// <para>
    /// Valid Authentication mode values are: <see cref="SmtpAuthentication.None"/>, 
    /// <see cref="SmtpAuthentication.Basic"/>, and <see cref="SmtpAuthentication.Ntlm"/>. 
    /// The default value is <see cref="SmtpAuthentication.None"/>. When using 
    /// <see cref="SmtpAuthentication.Basic"/> you must specify the <see cref="Username"/> 
    /// and <see cref="Password"/> to use to authenticate.
    /// When using <see cref="SmtpAuthentication.Ntlm"/> the Windows credentials for the current
    /// thread, if impersonating, or the process will be used to authenticate. 
    /// </para>
    /// </remarks>
    public SmtpAuthentication Authentication
    {
      get { return m_authentication; }
      set { m_authentication = value; }
    }

    /// <summary>
    /// The username to use to authenticate with the SMTP server
    /// </summary>
    /// <remarks>
    /// <note type="caution">Authentication is only available on the MS .NET 1.1 runtime.</note>
    /// <para>
    /// A <see cref="Username"/> and <see cref="Password"/> must be specified when 
    /// <see cref="Authentication"/> is set to <see cref="SmtpAuthentication.Basic"/>, 
    /// otherwise the username will be ignored. 
    /// </para>
    /// </remarks>
    public string Username
    {
      get { return m_username; }
      set { m_username = value; }
    }

    /// <summary>
    /// The password to use to authenticate with the SMTP server
    /// </summary>
    /// <remarks>
    /// <note type="caution">Authentication is only available on the MS .NET 1.1 runtime.</note>
    /// <para>
    /// A <see cref="Username"/> and <see cref="Password"/> must be specified when 
    /// <see cref="Authentication"/> is set to <see cref="SmtpAuthentication.Basic"/>, 
    /// otherwise the password will be ignored. 
    /// </para>
    /// </remarks>
    public string Password
    {
      get { return m_password; }
      set { m_password = value; }
    }

    /// <summary>
    /// The port on which the SMTP server is listening
    /// </summary>
    /// <remarks>
    /// <note type="caution">Server Port is only available on the MS .NET 1.1 runtime.</note>
    /// <para>
    /// The port on which the SMTP server is listening. The default
    /// port is <c>25</c>. The Port can only be changed when running on
    /// the MS .NET 1.1 runtime.
    /// </para>
    /// </remarks>
    public int Port
    {
      get { return m_port; }
      set { m_port = value; }
    }

    /// <summary>
    /// Gets or sets the priority of the e-mail message
    /// </summary>
    /// <value>
    /// One of the <see cref="MailPriority"/> values.
    /// </value>
    /// <remarks>
    /// <para>
    /// Sets the priority of the e-mails generated by this
    /// appender. The default priority is <see cref="MailPriority.Normal"/>.
    /// </para>
    /// <para>
    /// If you are using this appender to report errors then
    /// you may want to set the priority to <see cref="MailPriority.High"/>.
    /// </para>
    /// </remarks>
    public MailPriority Priority
    {
      get { return m_mailPriority; }
      set { m_mailPriority = value; }
    }

#if NET_2_0 || MONO_2_0 || NETSTANDARD2_0
    /// <summary>
    /// Enable or disable use of SSL when sending e-mail message
    /// </summary>
    /// <remarks>
    /// This is available on MS .NET 2.0 runtime and higher
    /// </remarks>
    public bool EnableSsl
    {
      get { return m_enableSsl; }
      set { m_enableSsl = value; }
    }

    /// <summary>
    /// Gets or sets the reply-to e-mail address.
    /// </summary>
    /// <remarks>
    /// This is available on MS .NET 2.0 runtime and higher
    /// </remarks>
    public string ReplyTo
    {
      get { return m_replyTo; }
      set { m_replyTo = value; }
    }
#endif

    /// <summary>
    /// Gets or sets the subject encoding to be used.
    /// </summary>
    /// <remarks>
    /// The default encoding is the operating system's current ANSI codepage.
    /// </remarks>
    public Encoding SubjectEncoding
    {
      get { return m_subjectEncoding; }
      set { m_subjectEncoding = value; }
    }

    /// <summary>
    /// Gets or sets the body encoding to be used.
    /// </summary>
    /// <remarks>
    /// The default encoding is the operating system's current ANSI codepage.
    /// </remarks>
    public Encoding BodyEncoding
    {
      get { return m_bodyEncoding; }
      set { m_bodyEncoding = value; }
    }

    #endregion // Public Instance Properties

    #region Override implementation of BufferingAppenderSkeleton

    /// <summary>
    /// Sends the contents of the cyclic buffer as an e-mail message.
    /// </summary>
    /// <param name="events">The logging events to send.</param>
    protected override void SendBuffer(LoggingEvent[] events)
    {
      // Note: this code already owns the monitor for this
      // appender. This frees us from needing to synchronize again.
      try
      {
        using StringWriter writer = new StringWriter(System.Globalization.CultureInfo.InvariantCulture);

        string t = Layout.Header;
        if (t != null)
        {
          writer.Write(t);
        }

        for (int i = 0; i < events.Length; i++)
        {
          // Render the event and append the text to the buffer
          RenderLoggingEvent(writer, events[i]);
        }

        t = Layout.Footer;
        if (t != null)
        {
          writer.Write(t);
        }

        SendEmail(writer.ToString());
      }
      catch (Exception e)
      {
        ErrorHandler.Error("Error occurred while sending e-mail notification.", e);
      }
    }

    #endregion // Override implementation of BufferingAppenderSkeleton

    #region Override implementation of AppenderSkeleton

    /// <summary>
    /// This appender requires a <see cref="Layout"/> to be set.
    /// </summary>
    /// <value><c>true</c></value>
    /// <remarks>
    /// <para>
    /// This appender requires a <see cref="Layout"/> to be set.
    /// </para>
    /// </remarks>
    protected override bool RequiresLayout
    {
      get { return true; }
    }

    #endregion // Override implementation of AppenderSkeleton

    #region Protected Methods

    /// <summary>
    /// Send the email message
    /// </summary>
    /// <param name="messageBody">the body text to include in the mail</param>
    protected virtual void SendEmail(string messageBody)
    {
#if NET_2_0 || MONO_2_0 || NETSTANDARD2_0
      // .NET 2.0 has a new API for SMTP email System.Net.Mail
      // This API supports credentials and multiple hosts correctly.
      // The old API is deprecated.

      // Create and configure the smtp client
#if NET_4_0 || MONO_4_0 || NETSTANDARD2_0
      using SmtpClient smtpClient = new SmtpClient();
#else
      SmtpClient smtpClient = new SmtpClient();
#endif
      if (!String.IsNullOrEmpty(m_smtpHost))
      {
        smtpClient.Host = m_smtpHost;
      }
      smtpClient.Port = m_port;
      smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
      smtpClient.EnableSsl = m_enableSsl;

      if (m_authentication == SmtpAuthentication.Basic)
      {
        // Perform basic authentication
        smtpClient.Credentials = new System.Net.NetworkCredential(m_username, m_password);
      }
      else if (m_authentication == SmtpAuthentication.Ntlm)
      {
        // Perform integrated authentication (NTLM)
        smtpClient.Credentials = System.Net.CredentialCache.DefaultNetworkCredentials;
      }

      using (MailMessage mailMessage = new MailMessage())
      {
        mailMessage.Body = messageBody;
        mailMessage.BodyEncoding = m_bodyEncoding;
        mailMessage.From = new MailAddress(m_from);
        mailMessage.To.Add(m_to);
        if (!String.IsNullOrEmpty(m_cc))
        {
          mailMessage.CC.Add(m_cc);
        }
        if (!String.IsNullOrEmpty(m_bcc))
        {
          mailMessage.Bcc.Add(m_bcc);
        }
        if (!String.IsNullOrEmpty(m_replyTo))
        {
          // .NET 4.0 warning CS0618: 'System.Net.Mail.MailMessage.ReplyTo' is obsolete:
          // 'ReplyTo is obsoleted for this type.  Please use ReplyToList instead which can accept multiple addresses. http://go.microsoft.com/fwlink/?linkid=14202'
#if !NET_4_0 && !MONO_4_0 && !NETSTANDARD2_0
          mailMessage.ReplyTo = new MailAddress(m_replyTo);
#else
          mailMessage.ReplyToList.Add(new MailAddress(m_replyTo));
#endif
        }
        mailMessage.Subject = m_subject;
        mailMessage.SubjectEncoding = m_subjectEncoding;
        mailMessage.Priority = m_mailPriority;

        // TODO: Consider using SendAsync to send the message without blocking. This would be a change in
        // behaviour compared to .NET 1.x. We would need a SendCompletedCallback to log errors.
        smtpClient.Send(mailMessage);
      }
#else
        // .NET 1.x uses the System.Web.Mail API for sending Mail

        MailMessage mailMessage = new MailMessage();
        mailMessage.Body = messageBody;
        mailMessage.BodyEncoding = m_bodyEncoding;
        mailMessage.From = m_from;
        mailMessage.To = m_to;
        if (m_cc != null && m_cc.Length > 0)
        {
          mailMessage.Cc = m_cc;
        }
        if (m_bcc != null && m_bcc.Length > 0)
        {
          mailMessage.Bcc = m_bcc;
        }
        mailMessage.Subject = m_subject;
#if !MONO && !NET_1_0 && !NET_1_1 && !CLI_1_0
        mailMessage.SubjectEncoding = m_subjectEncoding;
#endif
        mailMessage.Priority = m_mailPriority;

#if NET_1_1
        // The Fields property on the MailMessage allows the CDO properties to be set directly.
        // This property is only available on .NET Framework 1.1 and the implementation must understand
        // the CDO properties. For details of the fields available in CDO see:
        //
        // http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cdosys/html/_cdosys_configuration_coclass.asp
        // 

        try
        {
          if (m_authentication == SmtpAuthentication.Basic)
          {
            // Perform basic authentication
            mailMessage.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", 1);
            mailMessage.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", m_username);
            mailMessage.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", m_password);
          }
          else if (m_authentication == SmtpAuthentication.Ntlm)
          {
            // Perform integrated authentication (NTLM)
            mailMessage.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", 2);
          }

          // Set the port if not the default value
          if (m_port != 25) 
          {
            mailMessage.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserverport", m_port);
          }
        }
        catch(MissingMethodException missingMethodException)
        {
          // If we were compiled against .NET 1.1 but are running against .NET 1.0 then
          // we will get a MissingMethodException when accessing the MailMessage.Fields property.

          ErrorHandler.Error("SmtpAppender: Authentication and server Port are only supported when running on the MS .NET 1.1 framework", missingMethodException);
        }
#else
        if (m_authentication != SmtpAuthentication.None)
        {
          ErrorHandler.Error("SmtpAppender: Authentication is only supported on the MS .NET 1.1 or MS .NET 2.0 builds of log4net");
        }

        if (m_port != 25)
        {
          ErrorHandler.Error("SmtpAppender: Server Port is only supported on the MS .NET 1.1 or MS .NET 2.0 builds of log4net");
        }
#endif // if NET_1_1

        if (m_smtpHost != null && m_smtpHost.Length > 0)
        {
          SmtpMail.SmtpServer = m_smtpHost;
        }

        SmtpMail.Send(mailMessage);
#endif // if NET_2_0
    }

    #endregion // Protected Methods

    #region Private Instance Fields

    private string m_to;
    private string m_cc;
    private string m_bcc;
    private string m_from;
    private string m_subject;
    private string m_smtpHost;
    private Encoding m_subjectEncoding = Encoding.UTF8;
    private Encoding m_bodyEncoding = Encoding.UTF8;

    // authentication fields
    private SmtpAuthentication m_authentication = SmtpAuthentication.None;
    private string m_username;
    private string m_password;

    // server port, default port 25
    private int m_port = 25;

    private MailPriority m_mailPriority = MailPriority.Normal;

#if NET_2_0 || MONO_2_0 || NETSTANDARD2_0
    private bool m_enableSsl = false;
    private string m_replyTo;
#endif

    #endregion // Private Instance Fields

    #region SmtpAuthentication Enum

    /// <summary>
    /// Values for the <see cref="SmtpAppender.Authentication"/> property.
    /// </summary>
    /// <remarks>
    /// <para>
    /// SMTP authentication modes.
    /// </para>
    /// </remarks>
    public enum SmtpAuthentication
    {
      /// <summary>
      /// No authentication
      /// </summary>
      None,

      /// <summary>
      /// Basic authentication.
      /// </summary>
      /// <remarks>
      /// Requires a username and password to be supplied
      /// </remarks>
      Basic,

      /// <summary>
      /// Integrated authentication
      /// </summary>
      /// <remarks>
      /// Uses the Windows credentials from the current thread or process to authenticate.
      /// </remarks>
      Ntlm
    }

    #endregion // SmtpAuthentication Enum

    private static readonly char[] ADDRESS_DELIMITERS = new char[] { ',', ';' };

    /// <summary>
    ///   trims leading and trailing commas or semicolons
    /// </summary>
    private static string MaybeTrimSeparators(string s)
    {
#if NET_2_0 || MONO_2_0 || NETSTANDARD2_0
      return string.IsNullOrEmpty(s) ? s : s.Trim(ADDRESS_DELIMITERS);
#else
        return s != null && s.Length > 0 ? s : s.Trim(ADDRESS_DELIMITERS);
#endif
    }
  }
}

#endif // !NETCF && !SSCLI
#endif // NET_2_0
